1. Field of the Invention
The invention relates to a method of manufacturing cement bonded boards wherein a mixture of chip material, cement, additives and water is formed into a mat from which individual sections corresponding to the desired length of the board blanks are then produced, with the individual sections being pressed and subjected to hardening and seasoning processes, whereupon the boards are passed through a conditioning channel to achieve a moisture balance between the atmosphere and the board material and are subsequently subjected to at least an edge preparation process.
Cement bonded wooden boards enjoy a wide spectrum of use, above all in the construction industry, because these boards are relatively light, can be easily machined with normal tools, are resistant to rot, fungus attack and moisture and behave as a practically non-combustible material. Cement bonded wooden boards can be used in many cases without the surfaces requiring special finishing treatments. It is also not necessary to provide any special protection of the edges against moisture.
2. Prior Art
In order to economically manufacture cement bonded wooden boards of this kind, attempts have already been made in the known manufacturing methods to produce as little waste as possible. Waste material however necessarily occurs during manufacture because the pressed boards must be trimmed to size in order to ensure the required nominal sizes and exact edges.
In order to be able to make use of even the cement components of the waste material which arises it is already known to carry out an initial trimming operation on the pressed boards after they have been hardened, to form the trimmings into chips and to re-use the fine material fraction. This initial trimming step is accordingly carried out at the earliest possible time and the reason for this is that one would like to obtain fine waste material which can still be reactivated and which can be returned to the manufacturing cycle.
The material which is obtained at the end of the manufacturing process during the required edge preparation, and also during an eventual grinding stage, is not capable of being reactivated and thus has been a non-exploitable waste material which was not employed further within the context of the manufacturing process.
The problem underlying the present invention is to produce a significant improvement in the economics of the manufacture of cement bonded wooden boards and to improve the quality and dimensional stability of the finsished boards while simultaneously simplifying the overall process.